Pulse wave propagation velocity (PWV) has been a widespread device for evaluating vascular viscoelasticity non-invasively up to now. In this method, pulse waves must be measured using a cuff or the like attached at two or more places.
Meanwhile, there are known devices for evaluating vascular viscoelasticity by pulse wave measurement with a cuff attached at only one place, in which the pulse wave component of the cuff pressure is extracted, this extracted pulse wave component is subjected to temporal differentiation to calculate first derivation value and form a differential waveform, and in a state in which an external force substantially the same as or greater than the systolic blood pressure is being exerted on the blood vessel, the positive amplitude peak value within one pulse wave of the differential waveform is detected, the negative amplitude peak value is detected in a pulse wave in which the positive amplitude peak value was detected, the ratio of the peak value of the positive amplitude to the peak value of the negative amplitude is calculated, and then the vascular viscoelasticity is evaluated on the basis of this calculated ratio (see Patent Reference 1, for example).